Thoughts on batteries

[Joel]

I was at my local discount club today and decided to see what they had in batteries.  I noticed they carried Excel Marine dual purpose batteries.  These offer both marine starting and trolling power.  One was rated 70 AH and the other 95 AH.  Prices were $48 and $55 dollars respectivly.  Would these be good choices for powering just household lights via a tie-in (I envision separating my light circuits to a seperate breaker box that allows either inverter power or main-line power - never both - depending upon a switch) and 1200 watt inverter?

Thanks in advance.

Joel

[bob g]

not quite sure as to how much of a system you are anticipating, or its use, depth of use, frequency of use etc. many factors involved here to make an informed decision.

for just back up power for a few lights, that you don't plan on cycleing frequently from the batteries the dual purpose batteries my or may not be the way to go.

for instance the so called marine batteries or other so called deep cycle batteries are not truely deep cycle batteries, in that they likely won't take 80 percent DOD for more than a couple of hundred cycles before losing significant capacity. This is not a factor if you only plan on shallow DOD and infrequent use, then perhaps the cost analysis would support there use

other true deep cycle batteries come in a variety of life expectancies also , such as the trojan T105 and the like have a one year warranty and around 300 cycle life span. these would be a better choice over the use of dual purpose marine batteries and for not that much more money up front.

or you may need to step up to the Rolls/Surrette batteries some of which have as much as a 10 year warranty and average 3000 cycle life span. these are fairly expensive but when average out over the useful lifespan most times come out the hands down winner.

if i was planning a serious system that i wanted to last, i would probably check out the Rolls/ Surrette offerings to see how they fair in an analysis against the expected life span and useage.

probably you wouldn't want to invest more money in the long run on cheaper batteries, but then again first cost is certainly a factor for a lot of folks.

maybe a bit more info from you on your planned useage is in order.

bob g

[iFred]

The way I did it was, I bought a single battery and single 15 and 25 watt lamp with a single 500 watt cheapo inverter. (all of it low cost, less then $150) I then connected the three together and did some heavy testing over a period of about 2 weeks before I did anything else. I also connected several other loads just to see what was happening. The tests information then allowed me to calculate exactly what was required for my bigger system. It worked out well, but without that data, it's a shot in the dark (no pun intended).

This is what I would suggest in the beginning. It is a cheap method and gets you started and collecting data and doing some basic calcs which your going to need anyway later on. You need to know the amount of load (lights) the amount of batts (in amp hours), the recharging method -wind, solar, hydro, other, and know exactly how to match them all up...  When you do tests on single loads, you can then calculate what you will need overall and be able to better design a system that will do it perfectly as planned without extra expense. Planning, calculating and testing is key.

Once you have the data, then you can begin purchasing batts, inverters etc... and it will work as planned and you have in clearly in mind what needs to be done and what you are up against. Going blindly into it is a costly venture. That's my opinion.

What type of recharging method are you going to use wind, solar, other?   You did not specify.

Good Luck!

[nothing to lose]

"rated 70 AH and the other 95 AH.  Prices were $48 and $55 dollars respectivly"

Pesonally I would not consider it that good a deal based on amp hours.

$48/70= $0.69 per amp

$55/95= $0.58 per amp

Not being a true deepcyce also I would not expect as much from it as a real deep cycle for the life span or even the power output after a couple months.

For my Deep cycles I bought at Wal-mart awhile back I only paid $65 or less, might have been more like $60? 115 amp hours so, figuring the higher price just in case

$65/115= $0.57 a penny less per amp for a true deepcycle.

If I actually only paid $55-$60 then it's even less per amp, I looked at alot of batteries at that time and forgot the actual price of these, I know for certain it was not more than $65 each though.

Of course brands and such make a big difference, these are EverStart brand and I would not of course use the cost per amps comparing them to something like a Trojan!

As far as Everstart is concerned, I once thought that they would be a cheap junk battery, but I now think they may actually be pretty good! I use the auto everstarts in the cars and things that have killed other so called better brand of auto batteries have not effected those. Like several times the lights were left on in a car for several days, not even the dome lights would glow. Once charged and engine started the batteries charged good as new, they were older ones too. I've had newer "better brands" die with less abuse in less time, so Everstart might make some decent stuff??

As far as these deepcycles I do have, I don't have them in constant use, but I have abused them alot! Many times ran them down till the inveter shut off, also I used them to cart around and start extra cars in the yard (running stuff, I don't use) I have drained them till they would not turn over a VW Beetle, with that type of abuse they still seem good as new and no problems. I am sure I hurt them some as you should not do those things, but I didn't care because that's what I bought them for and why I bought cheap ones, but I can't tell I hurt them any and they are from 4/04.

 I would expect them to work well for a long time in normal use and cared for properly.

 But if I wanted the best and had the money, I would go Trojans or others made for RE apps for the best and longest life.

[ghurd]

The inverter seems a little large for a single lighting circuit.  1200w is a lot of light.  The loads should be looked at again?

I wouldn't use anything that says 'starting' on it anywhere.  Only 'trolling'. That's just me.

Around this time of the year, wallyworld usually clearances out the 'trolling' batteries. Got a group 24 (the smaller size) trolling battery a year or 2 ago for $29, this time of year. Was going to use 2 T-105s, but needed a battery quick. Still works fine.

The discount club has 6v golf cart batteries for about $48.50 each (need 2). Generic T-105s. Much cheaper for the initial installation cost.

I put a pair in about 6 years ago, and 4 pairs in 4 different systems about 4 years ago, with no problems yet.

G-

[troy]

Golf cart batteries have been a great solution for me.  And locally, they're not much more expensive than the so-called dual purpose batteries.

If the battery even lists Cold Cranking Amps (or CCA) it's a waste of money for a deep cycle application.  They get high CCA ratings by using many thin plates.  All that surface area is good for lots of amps over a few seconds (like starting a car) but very poor for long term durability.

Good luck and have fun!

troy

[juiced]

I dont agree about CCA thing. It may be true with most batteries, but i have a 'car-booster' power pack from Canadian tire that i charged when i bought, did about 35 boosts (its rated for 82 in a row or something) before charging, has been left numerously in the -35, and since bought (1 year exactly) has only been charged 4-5 times.

           It doesnt seem to have big issues... I can run my laptop all day from it, but my little 5w panel doesnt do squat to repleanish.

[nobicus]

You lot can get batteries really cheap!!!  The cheapest 95ah marine battery I have seen in the UK is $150 equivilant.  Thisa is why I am turning to junk car batteries for my emergency lighting.  Just had a thought though - as I live near the coast I wonder if there is a boat scrapyard I could approach for junk marine batteries to de-sulphate?

[ghurd]

Go where the big boys play with $million sail boats. Some of them change batteries every season. They may have a deal with somebody else already, like they did here.

Worth a shot?

[Joel]

Went back and double-checked to make sure I posted correctly and as usual I didn't have all my facts straight.  The brand is Exide and the ones I qoted prices on were not dual-purpose batteries (although they did have some of those) rather true deep cycle.  

As far as why I want to run a full 1200 Watt inverter - I'll be taking all the lights of my 2000 sq. ft house off grid.  The bypass switch will be to allow me back on grid if I am unable to get enough light through the solar array I am building to recharge the batteries during the day.  I live in central PA and some winter snows can get bad enough that I may not be able to clear the snow from panels for days as they will be positioned a-top a two story house at an odd angle (my roof slopes east-to-west).

Joel

[RC in FL]

Touched on a very controversial topic.

Personnally I have researched and thought about for a long time and have decided cost and convinence outweight other factors.

I have a Trace 3048 setup with 4x4 (16 battery array) of Delco Voyager class 27 (105AH) batteries.  Installed in Aug 99 and still going strong. Just went through two Hurricanes here in Palm Beach County and was the envy of the neighborhood.

I am going into sixth year on these same marine batteries.  Can not complain.

I don't let them discharge more then 40% from full charge and only that about 5 or 6 times over the last 5 years.  Most of time no more then 20%-30% discharge from full charge.

I have the float charge set a little low, about 13.35 vdc per battery to reduce water loss and use the temp compensation sensor that Trace has to optimize float voltage over temp.

I just advised a friend how to make a system for lighting, TV's, and run his refrigerator.

Refrig's are not too bad for run current, in 250 to 300 watt range but take 1200 to 1600 watt surge at startup. They seem to be okay with the cheapo 'modified sinewave' inverters. A 2000 watt modified sinewave inverter goes for about $120 these days.  

It will be about 95% efficient at 300 watts so 12v battery draw will be about 25 Amps.  Keep to the less then 40% discharge from full capacity.  You'll need at least four Everstart 29's in parallel to get a reasonable battery run time.

Get a little 1kw to 2k "lunchbox" quiet generator for about $380 to recharge batteries.

More $ then a 5KW gas powered generator but you won't keep your neighbors up at night with gen noise or have to keep going out to buy gas to feed it.  5KW gen's delivering an average load of 500 watts are very gas inefficient.

[nothing to lose]

"I dont agree about CCA thing. It may be true with most batteries, but i have a 'car-booster' power pack from Canadian tire that i charged when i bought, did about 35 boosts (its rated for 82 in a row or something) before charging, has been left numerously in the -35, and since bought (1 year exactly) has only been charged 4-5 times. "

I think your not looking at the battery for CCA with your booster your looking at the power it makes. Like using an inverter for 120Vac from 12vdc. It's not the same thing on both ends.

I have an everstart brand booster, hate it for a totally dead battery as it takes juice in the car battery for it to turn on. If the battery is totally dead then the unit will not work to start the car till you charge the cars battery. Real smart huh!

 I trick it buy using jumper cables from a weak battery in the next car, unit turns on I remove cables and start the car from the booster, what a pain!

I had a Craftsman Booster, alot of them had problems, mine was great till one day it got to full charge and started a loud beeeeeppppp type constant noise and I had to exchange it even though it still worked great because the buzzer never shut off.

For an exchange since they did not sell that one anymore I got a free booster by Xantrex! It has a built in inverter, 12v power outlet, digital display, light, aircompresser all built into it Yee ha!

  I was starting unused cars today with it for about an hour or more.

 How one small battery can do all that I don't know, but for certain it's a deep cycle.

Anyway all 3 of those have a deep cycle battery to power them stuck inside the back.

CCA or booster power is from something inside being powered by the battery, maybe large transformer or something but it makes more power for starting the engine than just connecting cables to a battery would.

One of the 3 I mentioned was supposed to be around a 500 amp booster, I forget which one though. Probably means CCA as I can't see any way to get 500amps out of the little battery inside it myself. Maybe a 20amphr sealed lead acid?? Though the Everstart does say something about a specail type to produce high power and such, but still just a deep cycle anyway.

Whatever they are inside it's still just the same as connecting an inverter basically, just works different for starting. Yours is probably same way unless it's something totally different than any I have had.

[troy]

You prob. know this already, but you can cut your load by 60-75% by switching to compact fluorescent if you haven't done so already.  The down side is that many fluorescent ballasts don't like cheap MSW inverters, significantly raising the cost of the whole project if you switch to a true sine wave inverter.

Good luck and have fun!

troy

[Joel]

I have compact or full florescents in the entire house with the exception of those areas needing short bursts of light - Bathrooms and closets - and those where it is not practical - outdoor candelaberas on a digital timer.  Haven't tried CF using a modified  sine so I'm not sure what the impact will be.  

Did check Wal-Mart the other day.  Sure Start Deep Cycle batteries with 115 AH for $55.  Think I'll pick one up with my next paycheck and see what I can do with it.  I understand these prefer 10+ Amp battery chargers.  Will my 6 Amp charger be too small to properly charge it or will it just take a longer time to charge?

Joel

[nothing to lose]

Will probably take longer to charge but charge fine.

I think any amps will work as long as your not kicking out to many and fry a battery.

Just lower amps will take alot longer to charge. 6amps at 12V is about 72watts an hour into your battery bank compared to 120watts at 10amps.

I been using a smart charger that goes up to 40amps for a set of batteries here, 480Watts an hour when it runs at max output.

Minus losses in the system so those numbers would actaully be less also.

Will 72watts an hour keep up with your usage? Wire and inverter and battery losses will add up a little also so your not getting 72watts of AC either.

[juiced]

I was reading last night that the CCA has alot to do with plate sizing in the batteries. Thicker plates for us. Thinner plates for CCA.

  I will have to stop using my booster pak for power because my now slightly more knowledgable self understands that the rate of charge from my array isnt enough to keep the battery healthy yet.

    I have to buy dinky-batts. lol.. i thought after spending like this, id have some decent juice.

    I mean, about 8 months ago when i started. Since then, its all been a paid education